heppeard



Jan. 6, 1948. s, HEPPEARDv 2,434,157

ELECTRONIC PHOTO TIMER Filed Nov. 18, 1946 2 Sheets-Sheet l afij eppeari Jan. 6, 1948- c. s. HEPPEARD 2,434,157

ELECTRONIC PHOTO TIMER Filed Nov. 1a, 1946 2 SheetS -Sheet 2 Patented Jan. 6, 1948 rim .1 h i mmrm'rmm OFFICE ."kpmliv rill. rh-rhd NIL "11135115" 1:: uhiime. Hi. 1H5 mm) "El-fins invention xc'katcs timer.

It is an object of this invention to provide an electronic phototimer for photoenlai'gers and printers, of operation 5 the platen switch whereby the length of exposure may be initially Figure 5 is a sehematie wiring set by an operator and the device will be t-heremodification of this phototimer,

Figure 6 is a fragmentary section taken on the ure 1.

i.- to an cluctrorxic photo- Figure 2 1:; u HulluHULLlC \Vil'illl; (H

Figure 3 is a Iraugxnenbary 5 line 3-3 of Figure 1,

Figure 4 is a frag itlll'illl), cation. taken on the mentary detailed section of diagram of a wanna? :fiertube comprisingiairectifierzisectiomand; an

and cathode: ofisaidrectifier. section; meanmconnectingasupply:circuitztoxsaidrdevice; a sat e .light and :811': exposure 'alightivconnected i to said';switch, said 1' means connecting: touthe-scathodesiof a said "sections, aswitch tin, saidnsupply; "circuit. means actuated by said plate: circuit ,fOD :operating gsaid switch ifor rselective connection to;;sa-id *safevlight or :said iexposure flight, means: supplying a --,charg e onithe: grid Of! said: :pentode- F section for; blocking said; plate --circuit;, andwmeans dissipating V said charge ron said grid; whereby-saidswitch 1wi1lube connectedwtoithe aotherzof :said lights; K

plifier :tu 'e zcomprisingiaz rectifier sectioniand an amplifier; section; aiplaiieicircuit i. across said :tube

connected: -to the plate; ofgsaidiamplifier :section and :ca-thode of said :rectifier section; means; con- 1 necting :a \supply circuit ,to; said --device,-v saidsupply circuit-Jconn'eotin cto the cathodes. of-,said

switch operating meanslconnecting theswitch'to the safe lightiirr one -position- .and. -to the .exposure light in another position;

11 An electronic phototimer comprising, a

switch for selectivelyzconneoting asaielight or an c ,exposureelight into the circuit of 'a source: of electric supply,a rectifieneamplifier tube havingsa :rectifierssectionzand atzpentodezsectlonri apswitch operatorrconnected'between said-rectifler and1pen- *todeisBct-ions operatin asaidz switch in cnmdirec- Jaionby current throughsa-id sections; a-condenser connecting to: the: grid of said: pentode' section for supplying an. electric chargethereto blockingflhe current itorsaid operator-and actuating said switch inttheother direction; and-means-dissipatingg said electric charge on :-said grid re-establishing the current itoasaid operator iior returning said- =oper- 'ator to-itsinitial -position,iand means :-varying the length of time of 'dissipatings the charge on said grid.-

12.- An electronicphototimer having aswitch for; connecting an .-exposure-1ight into an electric supply circuit and an'electro-magnetic operator for saidswitch-mormally holding ,said switch in exposure light :-circuit breaking aposition, rectifying means connected between one sideof said .operator and said. supply circuit, amplifying meanssconnected between the :other side of said operatortandsaid circuit, acondenser connected to;said amplifying meansifonblocking said circuit .to said ioperator, land a resistor connected ,across said .condenser for restoring said circuit after. aselected length of time, said switch con- Anec'ting said ..exposure light insaid supply circuit during .the time saidr-condenservblocks the circuit.

CHESTERTS. :HEPPEARD.

REFERENCES" 'CITE'D' Thetfollowingi references are of: record in the file --of this patent:

EUNITED STATES PATENTS Name Date Haar Jan. 10, 1939 "Number 2;1 43,c92tv Jam 6,, T1948. P. A. HERR 2,434,158

FILLED BAG SEWING MACHINE Filed Aug. 1, 1945 2 Sheets-Sheet l 

